Pneumatic tool.



PATENTED NOV. 5

O. W. THOMAS. PNEUMATIO TOOL.

APPLICATION FILED MAY 15.1905.

3 SHEETS-SHEET l.

l m l No. 870,523. PATBNTED NOV. 5, 1907. O. W. THOMAS.

PNEUMATIO TOOL.

APPLICATION FILED MAY 15.1905.

3 SHEETS-SHEET 2.

No. 870,523. PATENTED NOV. 5, 1907.

' O. W. THOMAS.

PNEUMATIO TOOL.

APPLICATION FILED MAY 15.1905.

s SHEETS-SHEET a.

426 63 www/fafa UNITED STATES' PATENT OFFICE.

OWEN w. THoMAs-OF sT. PAUL, MINNESOTA, A'ssIeNoR TOANNA HELWIG, OF sT. PAUL,

' MiNNEsOTA.

i 4PNE-Umano Toor..

matic Tools, of which the following is a specification.

This invention` relates to improvements in'pneumatic tools and particularly tohammers thatlare designed for riveting andfor operating chisels or other tools. l A

The-objects l have in- View are to provide a tool of this kind thatis simple in construction, in which the throttle or controlling valve may be easily operated and quickly adjusted so as to permit of any desired amount of movement, and in which a pneumatic cushion will be provided between the handle and the main cylinder of the tool.

A further object of the invention is to provide an improved valve for controlling the supply of air tothe reciprocating piston. i

lhe invention consists generally in the constructions and combinations, hereinafter-described and'particularly pointed out in the claims.

In the accompanying drawings, forming part of this specification;'Figure lisa longitudinal section of a tool embodying my invention. Fig. 2 is asimilar yiew showing the parts in a different position.A Fig. 3 is a section on line 3-3 of Fig." 2 lookinginthe direction of the arrow. Fig. 4 is a section online 4-4 of Fig. 1 looking in the direction of the arrow. `Fig.15 is a. section on line 5 5 of Fig. 1 looking in the direction of the arrow. Fig. 6 is'a section on line 6-6 of Fig. l looking in the direction of the arrow. Fig. 7 is a-sec tion on line 7-7 of Fig. 2 looking in the direction of the arrow. Fig; 8 is a section on line 8-8 of Fig. 2 looking in the direction of the arrow. Fig. 9 is a section of a portion of the cylinder andl lhandle showing.

means for regulating thethrottle opening. Fig. l0 is a partial longitudinal section showing a modified construction of throttle valve and a modied construct-ion of valve. Fig. .11 is a section similar to Fig. 10 showing the same construction of'valve at the other limit of its movementand showing the throttlevalve of Fig. 10 with a modified means for moving these-me. Fig.

l2 is a detail showing a modified means for operating the throttle valve.

1n all ofthe drawings, 2 represents the main cylinder of the tool, which maybe of any suitable size. This cylinder is open at one end and has arranged in its open end a sleeve 3 within which is arranged a shank 4of a suitable tool or tool-holder. This shank is provided with a head 5 adapted to receive the impact or blow from the reciprocating piston and the shank is preferably held in position by means of a screw 6 passing through the wall of the cylinder 2 and through the sleeve 3 and engaging a groove in the shank 4. Within Specification of LettersPatent.

Application-filed May l5. 1905- Serial No. 260.577.

resented Nov. 5, 1907.

thecylinder 2 is a reciprocating piston or hammer 7 which may be of any suitable size and which is adapted to reciprocate within the cylinder and to deliver blows in rapid succession to the head 5 of the tool or toolholder shank 4.

It will be understood that air under pressure is supplied to' the cylinder and, through a suitable controlling valve, is. conducted first to one end and then to i the other of the piston, and that; by this means, the

piston is rapidly 'reciprocated in the cylinder. It is preferable to conduct theair to the cylinder either throughthe handle or through a portion thereof, and Iprovide a cushioning device in the connection be- -tween the handle and the cylinder so as to do away with the 'jar upon the hand 'of the operator which otherwise would be experienced from the efecto the rapid blows delivered upon the head of the tool by the reciprocating hammer. I tisalso desirable to provide means arranged within the-tool for throttling the air *supplied to 'the cylinder.

At the handle end of the cylinder is a valve cham ber 8, the end 'of which is closed by a plug 9 and within this chamber is arranged a reciprocating valve 10.

This valve is provided with a central opening 11 and with`twoannular grooves 12 and 13. The central.

opening extends from the end oi the valve chamber y nearest the cylinder to a' point beyond the groove l2 ycommunicating with the two openings 16'and 16 communicating with the valve chamber 8. A second 'duct 17 communicates with the rear end -of the valve 'chartel ber and with the cylinder at a point near the middle thereof. A series of ducts 19 extend parallel with the valve chalnber and communicate therewith through the ports 20 and also through thx-'Q chamberv 21 which 95 extends around the valve chamber (see Fig. 6). An exhaust port 22 extends irom- Vthe valve chamber through the outer wall ofthe cylinder (s'ee Fig. 7). The I end of the cylinder nearest the handle is preferably screw-threaded and a head 23 is internally screwthreaded and is screwed on to the threaded end loi vthe cylinder. The plug 9 which fits into' the end of the .valve chamber4 is provided vwith, a flange 9 that its against the end oi the cylinder and the head 23 being screwed on until it cones in contact withV this flange, an annular air chamber 24 is formed around said iange. This air chamber communicates with all of the ports 19. The head 23 is provided with thef projecting inlet. tube 25 preferably formed integrally therewith and also with the tube 26 screwed into said head, or otherwise suitably secured thereto. The inlet opening 27 is provided in the head 23 and this opening communiopenings having therein the annular washers 29 and.

30 which fit upon the tubes 25 and 26, forming an airtight joint therewith. The tubc 25 is also provided with the annular washer 31, while the end oi the tube 26 is closed except for an opening 32 in the side wall thereof. A sleeve 33, also provided with an opening, is arranged outside of the tube26 and when the handle is drawn out, the openings in the tube and in the sleeve do not register and theair is shut off from the cylinder. These parts iorm av throttle valve, by means of which the supply of air to the 'cylinder may be regulated. By pushing the handle inward to the position shown in Fig. 2, the throttle is opened, and the air then passes through the handle and enters the tube 25, then passes into the chamber 24 and from this chamber into the series` of ports 19. The construction vshown provides an air cushion between the cylinder andthe handle and prevents any jar upon the hand of the operator when the device is in use.

When the parts are in the position shown in Fig. 1, the air passes. through the ports 19 and enters the cylinder and forces the piston .forward therein. As the piston approaches the end of its stroke, air fromthe cylinder passes into the duct 17 and from this duct enters the valve chamber in the'rear of the valve, forcing said valve from the position shown in Fig. 1 to that shown in 2. The opening to the rear end of the cylinder is now closed by the valve and the air now passes through the opening 20 around the` valve through the groove 13 and enters the duct 15, and, through this duct, enters the forward end of the cylinder, forcing the piston backward in the cylinder. As the piston vmoves backward in the cylinder, the air in advance of the piston' escapes through the central opening in the N'alv'e to and through the exhaust. As the piston reaches the limit of, its movement, a stem 34 on the end' of the piston, `the diameter of which is slightly greater than the opening in the center of the valve, closes the .central opening in the valve and the air within the cylinder, from the movement of the piston, is. compressed an'd throws the valve backward from the position shown in 2 to that shown in Fig. 1.

A=While the valve is in the position shown in Fig. 2 the rear e'nd of the cylinder is in communication with the exhaust opening through fthe central opening in the valve and'through the ducts communicating with the groove 12. ,When the'valve is moved,l to the position shown inFig. 1,lth e forward end of the cylinder is in communication ywith the exhaust opening through the port 16 (see Fig. DI By this means as the handle is pushed forward the throttle-valveis opened and the air, passing through the handle, is admitted irst to one end ofthe cylinder and then to the other and the piston is rapidly reciprocated in the cylinder.

In some instances I prefer to provide a direct communication for the air from the throttle valve to the inlet tube 25. For this purpose I may use the yconstruction shown in Fig. 9 oi the drawings. In this instance While the handle is hollow, the air does not pass through the rear extension oi the valve. the valve chamber somewhat longer to accommodate' it, but passes directly into the tube 25 through a suitable duct .35. The hollow handle in this instance serves as a dead air space and this air space serves as a cushion for the handle. I have also shown in this instance a regulating screw 36, by means of which thc opening into the inlet tube 25 may be partially closed.

In Fig. 10 of the drawings I have shown the'valv(` provided with a rear extension 37 and a groove 38 with a series o holes 39 extending from said groove through I have' also shown this extension of the valve and additional ports 40 extending 4from the ducts 19 into the valve chamber. With this construction, when the position of the valve is to be changed from that-.shown in Fig. l0 to that shown in Fig. 11,1the air from the cylinder passing through the duct 17, enters the groove 38 and moves the valve forward. A slight movement of the valve -closes the duct 17 and opens the port 40, permitting the air from the inlet openingsto enter the valve chamber in the rear of the valve and complete its forward movement, This enables me to secure a direct pressure from the inlet opening upon the rear of the valve so as to secure a positive and complete movement of said valve. 4

In Fig. 10 of the drawings I have shown a sliding throttle valve 43 adapted to be moved by a pressure pin 44 held in position by a screw 45. By pressing the thumb upon the head of the pin 44, the valve is moved backward'against the air pressure andthe air passes around said valve and enters the inlet tube 25, A regulating screw 46, provided with a stem 47, is arranged in the handle in line with the valve 43 and by means of this screw, the movement of the valve 43 may be regulated.` l i In Fig. 11 I have shown an inlet opening 48 provided in the handle and in this instance the tube 26 is replaced by acylindrieal plug 49, which simply acts as a guide for 'the handle. I have, in this instance, also shown a lever 50 arranged within the handle for the purpose of moving the throttle valve 43.

In Fig. 12 the pin 44, instead of'engaging the valve direct, engages one armof a bell-crank-lever 44 the air into first one end and then 4the other oiv the cylinder.

The parts of the tool are all easily made and require no line adjustment and, by means of the `construction described, a simple and reliable tool isprovided.

I claim as my invention: l

1. vIn a machine of the classvdescribed, the combination, with a main cylinder', a hummer piston arranged therein, and a vaivechamber arranged in vline with said cylinder and provided with an opening leading from,l said chamber inlt said cylinder, the duct 15 extending parallel and communicating with the cylinder at its forward end and with the valve` chamber' through the openings 16 and 1G', and the duct 17 communicating with the rear end of the valve chamber and with the cylinder at a point near the middle thereof, the-ducts 19 arranged parallel with the valve chamber and communicating therewith, or a reciprocating controlling valve 10 arranged in said valve chamber and having a reduced end arranged to. project through and close the opening leading from the chamber into said cylinder and having also the central opening 1 1, the annular grooves 12 and 13, and the series of ports 14 leading from the central opening into the groove 12.

2. In a machine of the class described, the-combination, with the main cylinder provided with a valve-chamber and a piston-controlling valve, of a h'ead secured upon said cylinder and provided with projections, one of which has an inlet opening extending through it and communicating with said valve chamber, a handle slidably secured upon said projections, and an air duct in said handle communiA eating with the inlet opening in said projection, substantially as described. f

3. In a machine of the class described, the combination, with a main cylinder, of a head screw threaded and provided with suitable projections, a handle slidably securedupon said projections, said handle being provided with an air inlet opening and one of said projections being pro` vided with an opening communicating with the interior of said cylinder, and a valve arranged in said handle and controlling the passage of air to said cylinder.

4. In a machine of the class described, the combination,

with a main cylinder provided with an air inlet tube projecting therefrom, of a handle slidably arranged upon said tube and provided with an air inlet and with an air pas- 'sage communicating with said tube, a valve arranged in said handle and controlling the passage of air to said tube and the adjusting device for regulating themovement of Said valve.

5. In a machine of the class described, the combination, with a main cylinder, provided with a reciprocating piston and a controlling valve, of an inlet tube projecting therefrom, a handle slidably arranged upon said tube, an air pus-4 sage arranged in said handle and communicating with said tube, a vulve arranged in the air passage in said handle, means for operating said valve and an adjusting device for limiting' the movement o f said valve.

In witness whereof, I have hereunto set my hand this 29th day of April 1905.

OWEN W. THOMAS.

Witnesses:

- C. G. HANsoN,

A. C. PAUL. 

